Re: [PATCH] SCSI: Replace semaphores with wait_even

[James Bottomley]

On Sun, 2004-10-24 at 16:06, Thomas Gleixner wrote:
> Hmm, strange. It works on two systems here and others using this
> modification had no problem either. 
> I will check again.

Yes, very strange given what the mistake is:

-               down_interruptible(&sem);
+               wait_event_interruptible(eh_wait, shost->eh_kill ||
+                               (shost->host_busy ==
shost->host_failed));

This condition is always true when the eh thread first starts because
the default quiescent state of a scsi host is

shost->host_busy = shost->host_failed = 0

so your change makes the eh_thread spin forever locking everything else
off the CPU.  On a UP system, this is a complete hang.

James


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